Screen or strainer for the blow-off of paper-stock boilers



(No Model.) v

B. P. MULLIN.

SCREEN OR STRAINER FOR THE BLOW OFF OF PAPER STOCK BOILERS.

No. 313,011. Patented Feb; 24, 1885.

Winesses, jZW/ iinn Frames Permit rricn.

BENJAMIN F. MULLIN, OF HOLYOKE, MASSACHUSETTS.

SCREEN Ofi STRAINER FOR THE BLOW-OFF OF PAPER-STOCK BOiLERS.

FJPATECIFICATION forming part of Letters Patent No. 313,011, dated February 2%, 1885.

- Application filed May 17, 1884. (No model.)

To all whom it may concern Be it known that I, BENJAMIN F. MULLIN, a citizen of the United States, residing at Holyoke, in the county of Hampden and Commonwealth of Massachusetts, have invented a new and useful Improvement in Screens for Strainers for the Blow-Offs of Paper-Stock Boilers, of which the following is aspecification, reference being had to the accompanying drawings, form ing a part thereof. 7

The objects of my improvements are, first, to provide a strainer that shall be readily accessible for cleaning; second, to provide a strainer that shall be readily detachable for cleaning or repairs; and, third, to provide a removable strainer that shall be firm and secure when in place. I attain these objects by the mechanism illustrated in the accompanying drawings, in which- Figure 1 is a front elevation of a portion of a stock-boiler of ordinary construction, showing the location of the ordinary and the improved strainer. Figs. 2 and 3 are sectional views of the ordinary strainers at present in use. Fig. 4: is a side view of my improved strainer in place. Fig. 5 is a front or plan view of said improved strainer, and Fig. 6 is a side view of said strainer partially detached for cleaning.

Similar letters refer tolike parts throughout the several views.

In Fig. 1 is shown a portion of an ordinary rotary boiler used for the treatment, under steam, of material used in the manufacture of paper.

A A, &c.. are sheets of iron or steel of which the cylindrical portion of the boiler is composed. B is a head, of which there is one for each end of the boiler. G is a shaft or trunnion attached to the head for the purpose of providing suitable bearings for the support and rotation of the boiler. The trunnions 0 rest in suitable journal-boxes, and gearing imparts rotary motion to the boiler. The boiler is provided with a suitable opening for the introduction and withdrawal of the stock. Steam is admitted to the boiler by a suitable pipe passing through or connecting with a passage formed in the trunnion O, and a pipe, D, attached to the boiler by the flange E, provides an exit for the steam. The pipes for inlet and outlet of steam are provided with suitable stop valves.

I11 operation theboiler is partially filled with stock and the necessary chemicals for acting upon it, steam is admitted, and the boiler is revolved for the purpose of thoroughly stirring and mixing its contents while acted upon by the pressure and heat of the steam. When this operation has been continued a sufficient length of time, steam is shut off and the rotary motion stopped; but before the contents of the boiler can be removed the steam under heavy pressure which is in the boiler must be released. For this purpose the blow-off. pipe D is provided. This is brought to the top of the boiler, its valve opened, and the steam blown out. I

If the opening from the boiler to the blowoff pipe were not protected by a strainer, the outrushing steam would carry with it some of the stock. To prevent the abstraction and waste of stock described, the blow-off opening is always covered by some sort of screen or cover, as indicated by the dotted line at F, Fig. 1. This screen as ordinarily made has the form shown in Figs. 2 and 3. The hemispherical piece F, with a flanged edge, f, is attached to the boiler-shell'A, around the blow-offopening D, by rivets, as at a, Fig. 2, or by bolts b, Fig. 3. The spherical portion of the piece F is properly perforated, and as a separator of stock from the steam admirably serves its purpose. In use, however, fragments of stock gradually work through the perforations and clog the apparatus, and it must be frequently removed for repairs. To remove the strainer shown in Fig. 2, the rivets a a,

. &c., must be cut, which is a laborious and can pensive operation. To. remove the piece Fin Fig. 3, a number of bolts must be taken out, and as, under the action of heat, pressure, and chemicals, said bolts 1 b, &c., are likely to be corroded in place, this work will usually be more expensive for removing and replacing than in the former case.

To obviate the difficulties mentioned and providea better strainer for this service is, in a word, the object of my invention.

My improved strainer is shown in Figs. 4,

5, and 6. I The strainer proper is shown at F. I displacement being prevented by the split It is of spherical form, ot'proper size, and with suitable holes, as shown, to meet the conditions respecting strength and capacity of the given service. At the line where the strainer F m( ets the boiler-shell A it comes to an edge,

(without flanging,) and is given the form of the surface which it meets, for the purpose of forming a close connection. A row of halfholes is made around said edge of the strainer, as shown, for the purpose of allowing it to come to a better bearing, and also permitting particles of stock to blowback into the boiler that would otherwise collect in the corner between the strainer-edge and the boilershell.

- The strainer F as described is attached to the boiler-shell in the following manner: To opposite sides of F are firmly riveted heavy ears G'G, as shown. Pairs of corresponding ears, H H, &c., are securely riveted'in the proper position on the shell A, as indicated, and heavy pins I I pass through the ears, firmly holding the parts in place, accidental pins K K.

\Vhen necessary to reach the concave surface of strainer F, a pin, I, is removed, F being swung back on the pin as a hinge, as in Fig. 6. F may be entirely separated by removing both pins. The relative position of the two hinges shown gives square resistance to the action of the stock when the boiler is in motionand prevents lateral strains.

I am aware that prior to my invention strainers have'been used in connection with the blow-offs of boilers, and such combination is not claimed, broadly; but

What I do claim as my'invention is- The combination of the strainer F, ears G G,

ears H H H H, and pins I I, substantially as 40 described, and for the purpose set forth.

BENJAMIN F. MULLIN.

Witnesses: H. K. HAWES,

H. H. SUWoRGY. 

